1. Field of the Invention
The present invention relates to a communication system including a femto base station. More particularly, the present invention relates to an access control method and a communication system therefor which provide a service for allowing a User Equipment (UE) to be directly connected to an Internet network through a femto Base Station (BS) without passing through an enterprise network.
2. Description of the Related Art
Initial mobile communication services were based on voice service. However, recently, the focus in the development of mobile communications technologies has shifted from voice service to data service. As a result of this shift, there has been an emergence of systems for providing high-speed data service, such as High-Speed Downlink Packet Access (HSDPA), mobile Worldwide Interoperability for Microwave Access (WiMAX), and the like.
The systems for providing such high-speed data service have a channel capacity of only a few Mbps. Accordingly, if too many User Equipments (UEs) located within a Base Station (BS) coverage area are using channels, data service speed of each UE drops to a few ten to a few hundred Kbps.
Various attempts to ensure data transmission speed of a few Mbps per UE have been made by installing a BS in a house or building interior to use fewer UEs. For example, a system using a femto BS, which is a BS installed interiorly, has been proposed to provide a service to approximately one to four UEs.
A femto BS is a type of micro BS which provides a communication service in an area having a radio of 100 meters or more. The femto BS is installed in an area, such as the interior of a house or building, where propagation of a macro cell is degraded, or in a shadow area, thereby compensating for quality of a communication service. The femto BS has low installation and maintenance costs by using a commercial Internet connection without passing through an indoor relay station. The femto BS also has superior mobility since it can be installed at any area where an Internet connection is provided.
Once installed, the femto BS increases data service capacity and coverage in a house or Small Office Home Office (SOHO) area. The femto BS, which has a small size, may limit connection only to UEs subscribed to an enterprise network to which the femto BS belongs. Currently, an access control technique for confirming whether a UE is permitted to access a specific femto BS has been discussed by standardization organizations, which are developing technical standards for femto BSs.
Meanwhile, a UE may access an Internet Protocol (IP) network through an enterprise network or may use a Local BreakOut (LBO) technique to directly access the IP network without accessing the IP network through an enterprise network. In order for a UE to receive an LBO service through a femto BS, the femto BS must perform additional access control to allow the UE to use the LBO service.
Therefore, a need exists for a method and communication system for allowing a UE direct access to an IP network.